The invention relates to a valve with a check valve, which are designed as an integrated component, in particular as an automotive hydraulic valve.
Valves in the automotive field should be able to perform numerous functions reliably over a long service life with a minimum of components. Hydraulic valves are used at many locations in a motor vehicle, inter alia as control valves for transmissions, pressure regulating valves for injection systems and camshaft adjusting valves. Camshaft adjusting valves are valves which, frequently used in a region of the cylinder head, control and set a camshaft adjuster, it being possible in particular for a vane-type camshaft adjuster to adjust the camshaft into an advanced or retarded position in relation to the crankshaft, depending on the pressurization of two hydraulic chambers. Owing to the application of torque by the camshaft to the camshaft adjuster, pressure blowbacks of the hydraulic medium, such as, for example, engine oil, may act on the camshaft adjusting valve. Similar situations may arise in transmissions due to load cycles. Separate check valves have been used hitherto for such pressure peaks.
There are numerous approaches in the patent literature which attempt to achieve check functions with the fewest parts possible. In this connection, reference is made to the publications U.S. Pat. No. 4,241,758, FR 525 481, GB 2 161 583 A, U.S. Pat. No. 2,781,059, U.S. Pat. No. 1,860,163, U.S. Pat. No. 894,286, U.S. Pat. No. 699,273, U.S. Pat. No. 5,323,806, U.S. Pat. No. 3,783,590 and U.S. Pat. No. 2,649,105, which all have one disadvantage or another. More suitable solutions can be found in U.S. Pat. No. 2,918,941, which discloses an external ring in a rail guide over uniformly distributed openings. An external, unclosed ring is shown in DE 2 043 002 A, in particular in FIGS. 7 and 8, which are intended to achieve a retaining function with a locking groove, a locking screw and uniformly distributed bores in an external encircling groove. A similar construction is known from FIG. 2 of DE 2 025 168 A, which illustrates a valve closing member with a pin serving as position securing means. From the field of compressor technology, EP 0 069 531 B1 shows in FIG. 10 a ring which can be clamped in and has two control grooves which are to be opened to varying degrees by a sliding member. Reference is also made to JP 55 072965 A.
A lamella opening is known from FR 996 121, having at one end a ring which at the other end is inserted in a double-walled clamping seat of a valve.
In EP 1 475 518 A one of the inventors of the present invention, inter alia, proposes how the through-opening in the sleeve of a valve can be cleverly designed so that the die-casting or injection-moulding die for producing the sleeve can be created without additional slides. FIG. 2 of the laid-open application shows that the production method can also be used to create through-openings which are uniformly distributed over the circumference.
A further type of internal, unclosed strap can be found in U.S. Pat. No. 3,882,891, which is locked by means of a screw and bearing plate to a fixed location on the pipe. To avoid the hitherto known locking solutions, in the solutions proposed in EP 1 291 563 A2 the applicant presented for the first time in the art a freely mounted closing element. In the publication, the principle according to the invention is explained by the fact that the spring force is chosen such that, at a predetermined pressure of the hydraulic medium, a bore can be opened by increasing or reducing the diameter of the closing element.